Abstract: A process for producing an olefin polymer employs a gas phase polymerization reactor in fluid communication with a vent column and a product discharge system. The discharge system can include first and second pairs of lock hoppers, where each pair includes an upstream lock hopper connected by a valve to the reactor and a downstream lock hopper connected by a valve to the upstream lock hopper and by a further valve to a product recovery system, and where a first cross-tie can be provided between the upstream lock hoppers of the first and second pairs of lock hoppers and a second cross-tie can be provided between the downstream lock hoppers of the first and second pairs of lock hoppers. Upon reaching the vent column's maximum removal capacity, additional gas can be removed from the reactor by reducing the frequency of opening the second cross-tie between the downstream lock hoppers.

Abstract: A process for producing an olefin polymer employs a gas phase polymerization reactor having a product discharge system comprising first and second pairs of lock hoppers, wherein each pair comprises an upstream lock hopper connected by valve means to the reactor and a downstream lock hopper connected by valve means to the upstream lock hopper and by further valve means to a product recovery system, and wherein a first cross-tie is provided between the upstream lock hoppers of the first and second pairs of lock hoppers and a second cross-tie is provided between the downstream lock hoppers of the first and second pairs of lock hoppers. Operation of the second cross-tie during product removal cycles is controlled in accordance with reactor pressure.

Abstract: The present disclosure relates to processes for production of polyolefins from olefin monomer(s) in a gas phase reactor using condensing agent(s) (CAs), and in particular relates to controlling condensed phase cooling in a gas phase reactor used to polymerize olefin monomer(s). The method may include introducing first and second condensing agent(s) into the reactor at ratio(s) determined by ascertaining a stick limit for the first condensing agent, calculating an equivalence factor relating the first and second condensing agents, ascertaining total allowable condensing agent, and calculating amount of the first condensing agent removed and replaced by the second condensing agent. The method may further include calculating the dew point limit of a gas phase composition including olefin monomer(s) as well as the first and second condensing agents; and determining if introducing a mixture comprising the olefin monomer(s) and the condensing agent composition would exceed the calculated dew point limit.

Abstract: This disclosure relates to processes for producing polyolefins in a gas phase reactor using condensing agent(s) (CAs), and real-time calculation of the ratio of one type of CA to another CA within a CA composition. This disclosure provides methods for controlling condensed phase cooling in a gas phase reactor used to polymerize olefins. The polymerization may employ one or more polymerization catalysts to polymerize one or more olefin monomers, and may include introducing a first condensing agent and a second condensing agent in a ratio of first condensing agent to second condensing agent, which ratio is calculated by ascertaining a stick limit for a first condensing agent, calculating an equivalence factor relating the first condensing agent and a second condensing agent, ascertaining a total allowable condensing agent, and calculating a first amount of the first condensing agent removed and replaced by a second amount of the second condensing agent.

Abstract: A process for producing an olefin polymer employs a gas phase polymerization reactor having a product discharge system comprising first and second pairs of lock hoppers, wherein each pair comprises an upstream lock hopper connected by valve means to the reactor and a downstream lock hopper connected by valve means to the upstream lock hopper and by further valve means to a product recovery system, and wherein a first cross-tie is provided between the upstream lock hoppers of the first and second pairs of lock hoppers and a second cross-tie is provided between the downstream lock hoppers of the first and second pairs of lock hoppers. Operation of the second cross-tie during product removal cycles is controlled in accordance with reactor pressure.